I have one diffuser set in about 3 foot of water that runs from noon to 2pm, cold weather or not. The last cold snap was pretty extreme for around here, and the system was only able to open about an 8 foot diameter hole which would freeze back over by the time I checked it at 5pm.
Am I doing it right? Is that a large enough hole to really add benefit to the pond? What are the risks of running it for longer and how much longer should I consider under the coldest of weather?

Maybe I do not even need winter aeration since I do not see ice over for more that a week or two between winter thaws.

Set me straight please.

Extra details:
¼ acre pond, 10 foot max depth, 6-7 foot ave depth (steep sides).
Diffuser is near bank in 5 feet of water, but 2 foot off the bottom.
Water temps before the pond freeze where 40 degrees top to bottom.
Yesterday’s ice was likely 5 inches thick except at the hole area where it had frozen back over (all speculation).

Can you drill a hole and measure water temps?

I could hack a hole with a sledge/hatchet off the dock, but it will be thawed in a few days as the temps will have gone from 5 degrees yesterday morning into the 60's on Sunday.

I can get surface temps from the hole easy enough since it is close to the shore which should represent overall temps in that area since the aerator would be running.

I took temps at the hole. 36 near the surface, 38 at a 5 foot depth.

My air stations have been running 24/7 in the shallows to keep a hole open. It has been so cold that the holes have been closed for three days now.

Hello.

Me too, with my air compressor running 24/7, my holes are frozen.

I would like to know how long I can stay like that, before I will have to make a hole with a hand auger.

A+

MNFish was telling me he has seen the air actually lift the ice off the water and make a dome over the diffuser which leads to the diffuser not cutting through the ice as fast.

I wonder if that could be happening to you guys?

QA - If you are only dealing with short periods of ice cover is Winter aeration and diffuser placement that critical?? When I initially asked about water temps for some reason I was thinking you were in Michigan. Big difference between there and Missouri.

IME, I have seen ice dooming just about every winter. It happens with the intermittent aeration systems I'm running and very cold temps. If I don't take care of it, the water with be closed off for weeks. Even after the cold weather subsides. Here is what I believe is going on. Maybe it applies to your situation as well.

First, the aerator shuts off as dark approaches (solar direct drive system). Next, a thick layer of ice develops over the diffuser(s).
Finally, the next day the compressor introduces the same amount of air it introduced the previous day. Unfortunately, the water movement is not enough to melt the thicker layer of ice. Since a frozen pond is now a closed system, and with new air being introduced, the entire sheet of ice is now under pressure.
The more pressure the more the ice rises off the pond. The more the ice rises off the pond the less contact of water movement from the water welling up from the diffuser.

Today we had very mild temps as compared to earlier in the week. I went to my place and "punched" holes above the diffuser. Moments after the air released, the ice was in contact with the water and a hole was once again created. The two pics show a before and after one hour apart.

A word of caution!!! If your water is under pressure and you "punch" a hole, be prepared. The water can spurt very high into the air and you will get quite a winter shower. Also, the ice that was stable below you may become less than stable. I am not kidding here....BE CAREFUL!!!!

Hello.

Thank you, here it is crazy, I live south of Montreal, 10 days ago it was -30c, today it's -5c, and in 2 days they said it will be +6c.

A+

Ultimately. This is my question. We may get two ice overs a winter that could last a few weeks a piece. Am I wasting electricy? Any tangible benefits to attempting to keep a 8 foot hole open?

You can see where I'm going.

QA - I am just going to throw out my OPINION since your not getting a lot of hits! I would GUESS, with that short of an ice over period, Winter aeration is not as critical. I think it would be more critical if the ice became buried under significant snow. I would also guess that as usual the answer is going to be "it depends" on each different pond. In the end you will probably have to have the DO data to avoid the dreaded "it depends" answer for your specific water.

Agreed. It all depends on the O2 demand in the pond, but a week or so shouldn't be too bad. I have seen a winterkill in a pond with medium O2 demand in a span of less than 3 weeks with a windmill system.

I agree. With only 2-3 weeks of ice cover you should not have to worry about aeration UNLESS the pond is shallow(5-8ft) and turbid with less than 2 ft of water clarity. Deeper ponds of 11-16ft can go 5 to 8 weeks of ice and snow cover without any DO problems. Ponds deeper than 16ft usually do not need to be aerated during winter if snow and ice cover melts by mid to late March.

MNFish2 - Are you happy with your solar aerator? Can you repost the link to how you built your solar aerator and approximate cost? I think I want one of those.

There are some limitations to this design but overall its performance has been acceptable. The one limitation is having to replace the pump every couple of years. You may not experience this since your location isn't in the frozen tundra. I was very surprised to see the compressor running when I went to the farm. -30 actual temps is way below the recommended lower limit operating temp.

I will search for the thread I posted for the bill of materials. It's basically made up of a 100w solar panel, 12V linear diaphram pump(Thomas 1.4cfm free flow), and a 12V LCB (linear current booster). The 12V LCB may be tough to source. At the time I was designing this system I had to get custom electronics made. That was quite awhile ago, maybe they are off the shelf components now. There is also a pressure gage and blow off valve.

MNFish would it be hard to scale up slightly? Say to a 2 CFM pump?

MNFISH2 if you find your old parts list thread, put it in your "watch list" so it will be easy to find in the future. You are going to get ask about this again and again.

I remember that experiment and build but did not mark it. Was a very nice non-battery setup. I remember at the time I was interested in it not for winter but for summer aeration in one of my ponds without electricity (across a creek so difficult also to run pipe). The LCB was to get enough current boost to initially supply the extra current to start the pump. Then the panel provided enough for the "run" current draw.

An alternative to the LCB might be a very small lithium rechargeable battery (like the ones that run fish feeders) but then a charging circuit would also need to be included to charge said battery.

Well, my pond currently has an estimated 210 pounds of stocked fish and better than average amounts of minnows, tadpoles, and crawdads...so I do not beleive it is overburdened with respect to bioload, but it has been muddy most of the winter with 6 to 12 inches of clarity (secchi disk readings), and there is little to no visible vegitation below the waterline. I still think that my aeration system is causing alot of the turbidity, but we have had a fair amount of inlfow too. With all that said I think I will keep the air running 2 hours a day just for peace of mind if nothing else.

QA - Maybe you could base your run times off of water temps?? Not sure what all the experts would think about that. Run the pump as much as you could while staying above a pre decided minimum temp. When water starts to approach the min temp shut the pump off and you should have an approximation of max run time. Not sure how you could go wrong with that??

I can see your train of thought and I like it. I wonder what a safe Temp Minimum would be?

Surface water temps the other day was at 36 degrees...that sounds pretty cold to me. I walked out on the dock and did some bouncing to see if the ice would give and it caused some waters to push up at the shoreline where the ice had thawed which pushed some minnows up onto the ice (they managed to wiggle back into the water). This tells me that at least the forage is content with 36 degrees.

Throughout the aerator development, design requirements were set for smaller, shallow, highly Eutropic waters.

Some random thoughts:
- I'm sure the system could be scaled up. At what cost, not sure.
- Knowing what I know now and what's available, I would go with a 24V system. Finding a "disposable" pump that could withstand my conditions, at a reasonable price, was a real challenge.
- Deeper water with these types of pumps could be a limiting factor
- Newer battery technology may be something to look into. My original designs failed when using batteries and the brutal cold. Also, the key to this system working in bitter cold is the very slow start up of the pump.

Scratch the lithium battery idea for winter. Forgot that they do not work when the internal battery temperature is below freezing. Kind of been a difficult point with some of the new electric cars. Would be fine in a warm weather use environment though.

I have used lithium batteries in below freezing temps fine. As with all batteries, they will lose some capacity when cold.

I could be wrong but I believe the problem comes in when you try to charge them in sub freezing temps when the internal battery temperature is also below freezing. As long as the internal battery temperature stays above freezing no problem. The damage comes from trying to charge sub-freez temperature battery.

Most if not all LION dedicated chargers will not charge a battery that is too hot or too cold to prevent damage or fire. IIRC.

QA - I have no idea what "comfortable" minimum temp would be for Bass, etc. Someone around here has to know though. I know the fat heads do fine at our place and last year we measured water temps at 33.0 degrees IIRC. I think Bass, etc is what you'd have to protect.

FHM, HSB, HBG, and RES are the only fish inhabitants.

Esshup just posted some O2/temps for his Indiana pond and the water was getting down to 34 degrees F.

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=501500#Post501500

I don't have any experience with O2 readings and don't know what fish are in his pond, but just looking at the water temps...34 degrees F is so close to freezing (assuming 34 is acceptable) that monitoring the temps and catching it in time to change the aeration schedule would be difficult with such a small window beteen his 34, your 33, my 36 degrees and actuall freezing.

My gut still suggests that keeping a small hole is marginally effective, but also low risk in potential harm considering this areas lack in ice coverage and extended cold weather.

MNFish2 Did you ever make and post the video of making your solar aeration setup? I found the posts that describe your system and how you made it. I had them in a file for the Archives Common Q&A section that I was creating about solar aeration. I added this thread to that list. Great informational posts - good work all around about this.

MNFISH Pictures of His Solar System
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=475582

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=449191&page=4

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=392612

Bill C - I agree!! I have been trying to twist his arm and make him post more!!

Thank you for the compliments Bill! I hope this helps others that don't have any other options, i.e no grid power access. I never shot the video but maybe this spring.

Jr- My wife is really upset now you got me posting info here again. "More forum stuff and more outdoor guys to talk on the phone with...GREAT!"....